Muffle



Aug. 7,;1945Q H.Y.H. HARRIS MUFFLE Filed July 3, 1942 2 Sheets-Sheet l INVENTOR IL/ENRVH HARP/s ATTORNEYS Au 7, 194's.

H. H. HARRIS MUFFLE Fild July 3, 1942 2 Sheets-Sheet 2 INVENTOR HENRY Mom/s 'ATTORNEYS.

v wiseto be -heattreatem's anwthem th weightof the charge itself," as well as.

I VlSlOIlZOf a muflie for use 'within a Patented 1 nay- .Applicatiu J, .te

inventiomtrelatesr toamufiles or containers employed in thenheat treatment of metalsni ln I use; the 'mufiles arg el rarged or loaded. with-trays containing. the metal; casti-ng's forgings. or rather- -subje'cted to; the strains and stresses caused byv heat of'the furnace; and usefu-l"ll-ties Mean so are usually provided side 'the mufiles'p upon 'which tw's'upport the charged trays orthe like, and thei weigli't'r'thereof is another factor having aired-verse marine ori the length 'ofi useful: life of "the muffle. --Thefurnace floor or to permit the circulation of have. relatively short "are. placed by :the

muffles are supported above %the r 5 3; 19 2;] eam constructedaccording to and embod heat entirely ar0um=tnemume. After some. use,

' -the m'uille "maywealren andfsag at certain-points,

"and unless givem'proper' support at those points, i

the must 1 "its useful life. may he -too quickly: terminated;

. I rhe ma-in object or my intention; 'tneriefcn iis the provision of a;

mufilei which is structurally re,- he-at weightrefiects minfor'ced against: the suiting frornius'e'. i j-Anothzerf object {or my invention is the provision t tudinally of" the *rnufilathe reinforcements icon "stitutifnganintegralpart of themufitew i Anotheriobjectcr mp-invention is theprovision iee u'me trons, the rein-forcem nt 'irithnhifllr v t 1 fitillanother object, of my invention is he pro vi'siofr"fof amufllewhich has structural reinforcements therein extending both transversely and longitudinally thereof, the lengthwise extending reinforcemen an integral part of the muffle.

Still another object, of my invention is the proheat treating furnaca means to support the muflle aboveand spaced, from the'furnace floor; and means to alter the distance betweenthe muffle and furnace floor at asingle pointor at a plurality of points, as may be needed or desired.

A still further object of my invention is the provision of a mufile having transverse corruga-' ristituting 'rails tions or bulges therearound, reversecorrugations 50 'or bulges on the floor of the muffle between the the muflle, which supports are secured Within 5 through the mufile, upon which the air develop cracks and shrinks;:1- and ts constituting rails forming of a'ir'iuffle which"has-structural reinforcements therein extending both transversely-and l'oflgfwhich is reinforeed aigainst use. condi permit of my specifically pointed on hereinbelow,

"the muflle supnorting' "cated by reference section; the bottom or l urther fob s of myf'irii'rejriti' n" will vious from'th'e; following "specificatio'riio a ia i w m ee1 rl vnfiee other obj ect's. will be specifically embed inventi' and sun "other objects will i e Figure 1 is 'a'pIarrvie'wIof' one for ventiom a Fig. '2 is a lo" g'itudinalsecti on theree Figf '4 "is asm'eg elevatiorim n showl muffle disposed w'thin; a heat treatingiurnalce Fig; 5' "is an enlarged: side 'elevation'al I mechanism: Fig. -6-*is'a'sectien tn'uriee; of F Fig. "l is a plan viewpf the trauma-wen the" muflle disposed within the furnace '5'":

'My'new and ijrhprovedmufife as 'a whole is infillial 111;: aiid" c'orriprises 'a'hollow, elongated shellof generally rectangular floor gortidn beingximii' cat'ed by reference numeral 12; "the outwardly bowed" side walls by"referencnumerals-=:M t4 and the "arched roof "or, top byhreferene mer'al 18-5 ,Muffie 'I 'B is formedbf a'.-1nuri1beru:of individual-sections 20; 2%; secured together in end:- to-end relationship," :will bewe'xplainetl below; Sections 20, 20 may be 'formed: as. by castin I or otherwise of suitable-high heatcanda eorrosion resisting alloy material; write .1

Eachsection 20 has formed therein a plurality of corrugations or bulges 22, 22, extending out from the body thereof circumferentially' of the shell. These corrugations or bulges 22, 22 provideincreased surface area for heat transfer from the furnace to the inside of the muflie, and also more uniform expansion and contraction underj'working conditions. In addition to these strengthening, transverse corrugations or bulges 22, 22 about each section, I also provide in each section a plurality of corrugations or bulges 24, 24 extending lengthwise of the shell H), on the floor or bottom transverse corrugations. These lengthwise corrugations 24, 24 project up into the muffle interior and have their tops flattened (see Figs. 2 and 3), and' when several sections are secured end-toend, they provide split rails extending lengthwise material be- |2thereof between the ing' treated may be disposed within the mufile.

These internal bulges 24, 24 also serve to strengthen the mufiie as well as providing increased surface area for heat transfer. 5 Furnaces in which muflies are employed are bed 50 has disposed therein two'pr more of U- 10 beam rails 5|, 5|, within which are placed trapped roller chains 52, 52 extending lengthwise of the,

furnace. The tops of the cylindrical rollers 54, 54,"

extend upwardly of the rails 5|, 5|, so as tobear" theunder- 1 against and make rolling contact with sides of shoes 56 secured to the mufile.

Shoes 56 have flattened bottoms, hanging, downwardly depending skirts 58, so as to straddle the rollers 54 of rails 5|. shoe bottom and integral therewith, I form a plurality of spaced skid rails 60, BlLthe topsof which are upwardly angled from each side towards the center thereof. Depending downwardly from the underside of the recesses defined by the internal bulges 24, I form a plurality of integral spaced ribs 62, 62, the bottom edges of which'arehorizontally straight. Ribs B2,. 62 oppose the upwardly angled skid rails 60,, 60 (see Figs. 5 and 6) and extend transversely of the furnace length.

with over- Atop" each flanges as 82, which may be provided with suitable closures during the heat treatment.

-With my corrugation bulge construction, my

muffle is provided with' increased resistance to claim and desire to secure by Letters Patent is:

5 comprising a casing, transverse corrugations exv1. A mufile for use in heat treating furnace tending entirely about the casing, and corrugations extending lengthwise of the casing on the bottom thereof between the transverse corrugationsoonstituting work supporting rails extending 0 lengthwise of the furnace.

A pair of'sliding blocks 64, 64 are disposed-ibe- 30 tween skid rails 60 and ribs 62. .These blocks are laterally apertured (see Fig. 6) and a threaded bolt 66 is passed through a suitable opening .68 in the outer block 64, engaging a; threaded opening 35 69 in the inner block; As the bolt 66 is .-rotated, blocks 64, 54 will be .drawn together, ridingup the inclined skid rails 60, GU'there-by raising that portion of the muffle resting thereon. I Obviously. any one or more may be -operated, as desired, to raise or lower any particular portion of the muffie resting thereon. I g

The shoe 5B is generally U-shaped in lengthwise section, and the sides thereof extend into the recess. defined :by; bulges 24. formed on each end of the shoes, about which a loop or bail "I2 is passed to secure the shoes to the muflle. The ends of the loop or bail may be spot welded or otherwise secured to the muflle.

Ears H1 are 5 The individual sections 20, 20 are secured. astso by welding in end-to-end relationship; and an encircling collar 14 is provided to reinforce the joint. Stops'l6 are provided near theend of each section to locate the collar 14 and securesame in position over the joint.

The ends of the mufile are flared outwardlyinto underside of the casing.-

2. A'muffle for use in heat treating furnaces comprising a relatively elongated casing, reinforcements therein extending'transversely of the casing and circumferentially thereof,. and additional reinforcements extending longitudinally of the casing and between'the transversereinforcements, both sets of reinforcementscomprising bulges, the transverse bulges extending outwardly from the casing, and the longitudinal bulges projecting into the casing constituting workjsupporting rails extending lengthwise thereof,

3. A muffie for use in a heat treating furnace and means to support same in spaced relation to thefurnace floor the muflle comprising an elongated casing having a plurality of lengthwise spaced-apart bulges extending: circumferentially of the casing and outwardly. therefrom, the casing also having a plurality of lines of bulges on the bottom thereof, the bulges being .endwise spaced apart lengthwise of the casing and extending up intothe interior thereof. between the circumferential bulges, the circumferential bulges and the lengthwise bulges defining recesses to receive the casing supporting'means.

4. A muffle for use in a heat treating furnace and means to support same therewithin in; spaced relationito the furnace floor; the muflle comprising an elongated. casing, a plurality of parallel lines of endwise spaced-apart recesses on the bottom of the casing, bulging upwardly into the interior thereof,the tops of, the bulgesconstituting split work supporting rails extending lengthwise of the furnace, and the supportingmeans being received and secured within the recesses on the HENRY H. HARRIS. 

